package com.zhuang.jdk8.java8;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.function.Supplier;

/*
 * Java8 内置的四大核心函数式接口
 * 
 * Consumer<T> : 消费型接口
 * 		void accept(T t);
 * 
 * Supplier<T> : 供给型接口
 * 		T get(); 
 * 
 * Function<T, R> : 函数型接口
 * 		R apply(T t);
 * 
 * Predicate<T> : 断言型接口
 * 		boolean test(T t);
 * 
 */
public class TestLambda3 {
	public static void main(String[] args) {
		test1();
		test2();
		test3();
		test4();
	}
	// Predicate<T> 断言型接口：

	public static void test4() {
		List<String> list = Arrays.asList("Hello", "atguigu", "Lambda", "www", "ok");
		List<String> strList = filterStr(list, (s) -> s.length() > 3);

		for (String str : strList) {
			System.out.println(str);
		}
	}

	// 需求：将满足条件的字符串，放入集合中
	public static List<String> filterStr(List<String> list, Predicate<String> pre) {
		List<String> strList = new ArrayList<>();

		for (String str : list) {
			if (pre.test(str)) {
				strList.add(str);
			}
		}

		return strList;
	}

	// Function<T, R> 函数型接口：

	public static void test3() {
		String newStr = strHandler("\t\t\t 我大尚硅谷威武   ", (str) -> str.trim());
		System.out.println(newStr);

		String subStr = strHandler("我大尚硅谷威武", (str) -> str.substring(2, 5));
		System.out.println(subStr);
	}

	// 需求：用于处理字符串
	public static String strHandler(String str, Function<String, String> fun) {
		return fun.apply(str);
	}

	// Supplier<T> 供给型接口 :

	public static void test2() {
		List<Integer> numList = getNumList(10, () -> (int) (Math.random() * 100));

		for (Integer num : numList) {
			System.out.println(num);
		}
	}

	// 需求：产生指定个数的整数，并放入集合中
	public static List<Integer> getNumList(int num, Supplier<Integer> sup) {
		List<Integer> list = new ArrayList<>();

		for (int i = 0; i < num; i++) {
			Integer n = sup.get();
			list.add(n);
		}

		return list;
	}

	// Consumer<T> 消费型接口 :

	public static void test1() {
		happy(10000, (m) -> System.out.println("你们刚哥喜欢大宝剑，每次消费：" + m + "元"));
	}

	public static void happy(double money, Consumer<Double> con) {
		con.accept(money);
	}
}
